At some time near the end of the sixth century bce, Hecataeus of Miletus paid a visit to Egypt in the course of his extensive travels around the Mediterranean and the Black Sea. There, as Herodotus reports, the logographer and genealogist had a celebrated encounter with certain Theban priests. When Hecataeus recited his genealogy and traced his descent back to a god in the sixteenth generation, the Egyptian priests refuted the Greek's assertion of such recent divine ancestry by showing him 345 wooden statues, each set up by a high priest in his lifetime. The images represented an unbroken lineage of sons succeeding to their father's office, each of whom was a man not a god. Herodotus, too, claims he was shown these same images, though he had wisely refrained from reciting his genealogy.

This anecdote is the critical beginning of a Greek tradition on the knowledge of Egyptian priests – a knowledge which derives from the vast antiquity of Egyptian civilization, and is preserved through the records of a long-standing written culture. In this episode, Herodotus constructs a scene in which Greek traditions on the past are trumped by an Egyptian priest, vividly conveying the infancy of Greek civilization in the face of Egypt's great antiquity. This anecdote has also been critical in modern scholarly constructions of the relationship between Greek civilization and Egyptian. Some have seen it as a decisive moment in the intellectual biographies of the early Greek historians, others an attractive and useful fiction.

From 1909 to 1912, French archaeologists led by Pierre Roussel carried out the first systematic excavation of structures in the neighborhood of the Inopos valley on the island of Delos. This was an area in which inscriptions related to the cult of Egyptian gods had been discovered as early as the seventeenth century, but with the exception of some incomplete digs in the nineteenth century, the exploration of a possible sanctuary dedicated to Egyptian divinities had taken a back seat to scholarly interest in the cult of Apollo. By the end of his excavations, however, Roussel had unearthed the third of three sanctuaries (A, B, and C) devoted to the god Sarapis. Roussel designated the last one of these that he found not Sarapieion C (as one might suppose from the order of their discovery), but Sarapieion A. He found the reason for this sequence in a lengthy Greek inscription that he uncovered there in 1912.

In prose and hexameters, this text, dated roughly to the end of the third century bce, tells of the sanctuary's foundation: a tale of humble beginnings, a struggle for survival, and ultimate success through the intervention of Sarapis. The most prominent event in this brief history is the victory of the Egyptian priest Apollonios over certain men who brought a lawsuit against him and the newly built sanctuary.

When Thessalos wrote of his quest for magical wisdom in Thebes, he gave the impression that he was seeking knowledge from an ancient community that was beginning to fade away. There were wise and learned men there, but only one of them could deliver on his promises of magic. When he found that venerable old priest, he walked with him in deserted parts of the city, and he made his desperate plea for knowledge in a sacred precinct no longer filled with people and the sounds of worship, but gripped by silence. While Thessalos appropriated and supplanted the authoritative voice of Egyptian wisdom, he also evoked the image of a “vanishing Egyptian.” The act of capturing and preserving alien wisdom, as in so many other cases, went hand in hand with a fable of its ever-receding sources. The magic of empire has the power to make people disappear. On the other hand, History, Michel de Certeau has taught, is the attempt to recuperate vanished voices and a vanished past in the form of a text. Thessalos' story reminds us that some of these voices have disappeared and some have been disappeared. If all pasts are absent, some pasts are more absent than others. Their absence is produced in particular texts and in particular contexts, both ancient and modern. And if the past is an “other” country, the Egyptian past has been doubly other, especially when considered together with the Greek past, and through the mediation of Greek texts alone.

Cumont dated Thessalos' treatise to the middle of the first century ce on the basis of its dates for the sun's ingress into the signs of the zodiac. Since astrologers and astronomers in the early Roman period used sidereal rather than tropical longitudes in marking the positions of the sun, the moon, and the planets, the date at which the sun entered a particular sign was delayed by about a day every 100 years, according to ancient estimates. This allowed Cumont to estimate when the treatise was composed by comparing Thessalos' dates to a calendar of solar ingresses interpolated from information found in Varro's De re rustica, which was composed in 37 bce. The basic principle is sound, but Cumont's dating can now be checked and adjusted using a much larger volume of astronomical data that has been gathered in subsequent studies of ancient astronomy and astrology.

In comparing modern calculations with those of twenty-eight horoscopes recorded in Vettius Valens dating from 37 to 188 ce, Neugebauer and Van Hoesen found that calculations of the sun's longitude by the second-century ce astrologer were greater than modern ones by 2 to 7 degrees, and that the differences tended to decrease in the horoscopes calculated for later dates. This decreasing trend, they observed, was roughly commensurate with the precession of the equinoxes. They concluded that these calculations were based on tables which differed from modern calculations by ca. +5° in 50 ce and ca. +3.5° in 160 ce, figures which were comparable to the deviations observed in the Demotic and Greek planetary tables preserved on papyrus.

In his classic study, Alien Wisdom: The Limits of Hellenization, Arnaldo Momigliano explored what he called “an intellectual event of the first order, the confrontation of the Greeks with four other civilizations” in the Hellenistic period: Romans, Celts, Jews, and Iranians. Remarkable for its absence from his account is the ancient civilization of the Egyptians, which had long fascinated the Greeks, and, after the conquests of Alexander, confronted them more directly than ever before. Momigliano's argument for excluding Egypt from his lectures was twofold. First, “there was no dramatic change in the Greek evaluation of Egypt during the Hellenistic period.” Egypt from Homer through Herodotus had been a fantastical land of “strange customs” and “unusual knowledge” and remained so into the Hellenistic period. Secondly,

Momigliano went on to state that “the Hellenistic Greeks preferred the fanciful images of an eternal Egypt to the Egyptian thought of their time.”

(1) † Harpokration to Caesar Augustus, greetings.

Since many in their lives have tried, august Caesar, to hand down many marvelous things, but none have been able to bring their promises to completion, owing to the darkness of fate pressing upon their thoughts, I think that I alone among the men of all time have accomplished something marvelous <and known to few>. (2) For having set my hand to matters which transcend the limits of mortal nature, I have, through many trials and dangers, brought to these matters the proper completion. (3) After I had practiced letters in the regions of Asia and had become better than everyone there, I determined to have profit from the knowledge for a time. (4) And having sailed to much-desired Alexandria with a great deal of money, I went around to the most accomplished of the scholars and because of my industry and quick wit I was praised by all. (5) But I also went continually to the lectures of the dialectical physicians, for I greatly desired this knowledge. (6) When it was time to return home, and as my medical studies were already duly progressing, I went around to the libraries searching out <the necessary material>. I found a book by Nechepso containing twenty-four remedies for the entire body and every disease, according to the zodiac, by means of stones and plants, and I was amazed at the wonders it promised. But it was, as it seems, the empty delusion of royal folly.